Heterogeneous integration of 3D Si and III-V vertical nanowire structures for mixed signal circuits fabrication

ABSTRACT

A method of forming Si or Ge-based and III-V based vertically integrated nanowires on a single substrate and the resulting device are provided. Embodiments include forming first trenches in a Si, Ge, III-V, or Si x Ge 1-x  substrate; forming a conformal SiN, SiO x C y N z  layer over side and bottom surfaces of the first trenches; filling the first trenches with SiO x ; forming a first mask over portions of the Si, Ge, III-V, or Si x Ge 1-x  substrate; removing exposed portions of the Si, Ge, III-V, or Si x Ge 1-x  substrate, forming second trenches; forming III-V, III-V x M y , or Si nanowires in the second trenches; removing the first mask and forming a second mask over the III-V x M y , or Si nanowires and intervening first trenches; removing the SiO x  layer, forming third trenches; and removing the second mask.

TECHNICAL FIELD

The present disclosure relates to methods of manufacturing complimentarymetal-oxide-semiconductor (CMOS) devices. The present disclosure isparticularly applicable to field effect transistor (FET) structures withvertical nanowire channels.

BACKGROUND

Traditionally, CMOS fabrication has been divided into digital and analogdevice fabrication techniques. Known electronic devices employ separatedigital and analog chips having different (i) substrate, (ii) voltage,(iii) frequency, and (iv) fabrication requirements, all of whichincrease chip real estate demands and fabrication complexity.

Reducing the supply voltage of high performance FETs is a knowneffective approach for power scaling. In addition, silicon (Si)-basedCMOS technologies require gate-architecture changes to suppress theshort-channel effect and OFF-state leakage current. Further, usingdifferent channel materials is known to enhance the ON-state current ata lower electrical field and, therefore, enable lower power consumption.

A need therefore exists for methodology enabling fabrication ofintegrated digital and analog circuits on a single substrate that isscalable and compatible with current integrated circuit (IC) fabricationtechnology, and the resulting device.

SUMMARY

An aspect of the present disclosure is a method of forming Si orgermanium (Ge)-based and material group III-V-based verticallyintegrated nanowires on a single substrate.

Another aspect of the present disclosure is a Si or Ge-based andIII-V-based vertically integrated CMOS nanowire device formed on asingle substrate.

Additional aspects and other features of the present disclosure will beset forth in the description which follows and in part will be apparentto those having ordinary skill in the art upon examination of thefollowing or may be learned from the practice of the present disclosure.The advantages of the present disclosure may be realized and obtained asparticularly pointed out in the appended claims.

According to the present disclosure, some technical effects may beachieved in part by a method including: forming first trenches in a Si,Ge, III-V, or silicon germanium (Si_(x)Ge_(1-x)) substrate; forming aconformal silicon nitride (SiN), SiO_(x)C_(y)N_(z), or direct plasmanitride (DPN) layer over side and bottom surfaces of the first trenches;filling the first trenches with silicon oxide (SiO_(x)); forming a firstmask over portions of the Si, Ge, III-V, or Si_(x)Ge_(1-x) substrate;removing exposed portions of the Si, Ge, III-V, or Si_(x)Ge_(1-x)substrate, forming second trenches; forming III-V, III-V_(x)M_(y), or Sinanowires in the second trenches; removing the first mask and forming asecond mask over the III-V, III-V_(x)M_(y), or Si nanowires andintervening first trenches; removing the SiO_(x) layer, forming thirdtrenches; and removing the second mask.

Aspects of the present disclosure include doping an upper 50 nanometer(nm) to 500 nm of the Si, Ge, III-V, or Si_(x)Ge_(1-x) substrate priorto forming the first trenches. Other aspects include forming the firsttrenches by: forming a preliminary SiN layer over the Si, Ge, III-V, orSi_(x)Ge_(1-x) substrate; forming a silicon dioxide (SiO₂) layer overthe preliminary SiN layer; patterning the SiO₂ and preliminary SiNlayers; and etching a portion of the Si, Ge, III-V, or Si_(x)Ge_(1-x)substrate through the patterned preliminary SiN and SiO₂ layers. Furtheraspects include removing the SiO₂ and preliminary SiN layers prior toforming the SiN and SiO_(x) layers in the trenches. Another aspectincludes, wherein the substrate is formed of Si, Ge, or Si_(x)Ge_(1-x),forming the III-V or III-V_(x)M_(y) nanowires by: depositing an aluminum(Al), nickel (Ni), or gallium (Ga) nanoparticle in each second trench byself-assembly in sol-gel or by direct deposit; and growing the III-V orIII-V_(x)M_(y) nanowires to a desired height by a metal catalystvertical vapor liquid solid (VLS) growth or chemical vapor deposition(CVD). Additional aspects include the metal catalyst being formed of Ni,Al, gold (Au), silver (Ag), titanium (Ti), erbium (Er), platinum (Pt),palladium (Pd), indium (In), Tin (Sn), antimony (Sb), Zirconium (Zr),vanadium (V), hafnium (Hf), tungsten (W), cobalt (Co), tantalum (Ta),lanthanum (La), ruthenium (Ru), molybdenum (Mo), Ga, or iron (Fe). Otheraspects include wherein the III-V or III-V_(x)M_(y) nanowires are notgrown to a full width of the second trenches, forming an oxide ornitride layer between each III-V or III-V_(x)M_(y) nanowire andsidewalls of the corresponding second trench. Further aspects includewherein the substrate is formed of III-V, forming the Si nanowires by:depositing a Ni or Au nanoparticle in each second trench byself-assembly in sol-gel, metal organic chemical vapor deposition(MOCVD), or atomic layer growth (ALD); and growing the Si nanowires to adesired height.

Another aspect of the present disclosure is a method including: forminga substrate stack including an amorphous silicon (a-Si) followed by n orp doping or doped polysilicon (poly-Si) layer, and a silicon oxycarbide(SiOC) layer; forming first and second groups of trenches in thesubstrate stack down to the doped a-Si or poly Si layer of the substratestack; forming a first mask over the second group of trenches; formingSi, Ge or Si_(x)Ge_(1-x) nanowires in the first group of trenches;removing the first mask and forming a second mask over the Si, Ge, orSi_(x)Ge_(1-x) nanowires; forming III-V or III-V_(x)M_(y) nanowires inthe second group of trenches; removing the second mask; and planarizingthe Si, Ge, or Si_(x)Ge_(1-x) and III-V or III-V_(x)M_(y) nanowires downto the SiOC layer.

Aspects of the present disclosure include forming the substrate stackby: forming a Si substrate; forming a buffer oxide layer over the Sisubstrate; forming the a-Si or doped poly-Si layer over the oxide layer;forming a first SiN layer over the a-Si or doped poly-Si layer; formingthe SiOC layer over the first SiN layer; and forming a second SiN layerover the SiOC layer. Other aspects include forming the trenches withinthe substrate stack by: self-aligned double patterning (SADP) orself-aligned quadruple patterning (SAQP), direct surface assembly(nanoimprint), or extreme ultraviolet (EUV) lithography. Further aspectsinclude forming the Si, Ge, or Si_(x)Ge_(1-x) nanowires by: depositing aNi or Au nanoparticle in each of the first group of trenches byself-assembly in sol-gel or by metal organic chemical vapor deposition(MOCVD), atomic layer growth (ALD); and growing the Si, Ge, orSi_(x)Ge_(1-x) nanowires to a desired height. Another aspect includesforming the III-V or III-V_(x)M_(y) nanowires by: depositing an Al, Ni,or Ga nanoparticle in each of the second group of trenches byself-assembly in sol-gel or by MOCVD, ALD; growing the III-V orIII-V_(x)M_(y) nanowires to a desired height by a metal catalystvertical VLS growth, chemical vapor deposition (CVD) growth with in-situdoping during growth; and removing the second mask prior to planarizingthe Si, Ge, or Si_(x)Ge_(1-x) and III-V or III-V_(x)M_(y) nanowires.Additional aspects include forming the III-V or III-V_(x)M_(y) nanowiresof a combination of indium phosphide (InP), indium arsenide (InAs),gallium nitride (GaN), or gallium arsenide (GaAs). Other aspects includethe metal catalyst being formed of Ni, Al, Au, Ag, Ti, Er, Pt, Pd, In,Sn, Sb, Zr, V, Hf, W, Co, Ta, La, Ru, Mo, Ga, or Fe.

A further aspect of the present disclosure is a device including: asubstrate; a first group of Si or Ge-based vertically integratednanowires formed on the substrate; and a second group of III-V-basedvertically integrated nanowires formed on the substrate, separated fromthe first group, the first and second groups of vertically integratednanowires being formed of heterogeneous materials.

Aspects of the device include the substrate being formed of Si, SiGe,III-V, a combination thereof, or a substrate stack. Other aspectsinclude the substrate stack being formed of sequential layers ofsilicon, oxide, a-Si or doped poly-Si, SiN, SiOC, and SiO_(x)C_(y)N_(z).Further aspects include the first group of Si or Ge-based verticallyintegrated nanowires being formed of Si, Ge or Si_(x)Ge_(1-x).Additional aspects include the second group of III-V-based verticallyintegrated nanowires being formed of III-V or III-V_(x)M_(y)

Additional aspects and technical effects of the present disclosure willbecome readily apparent to those skilled in the art from the followingdetailed description wherein embodiments of the present disclosure aredescribed simply by way of illustration of the best mode contemplated tocarry out the present disclosure. As will be realized, the presentdisclosure is capable of other and different embodiments, and itsseveral details are capable of modifications in various obviousrespects, all without departing from the present disclosure.Accordingly, the drawings and description are to be regarded asillustrative in nature, and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawing and in whichlike reference numerals refer to similar elements and in which:

FIGS. 1 through 14 schematically illustrate a process flow for formingSi or Ge-based and III-V-based vertically integrated nanowires on asingle substrate for mixed signal circuits, in accordance with anexemplary embodiment; and

FIGS. 15 through 22 schematically illustrate another process flow forforming Si or Ge-based and III-V based vertically integrated nanowireson a single substrate for mixed signal circuits, in accordance with anexemplary embodiment.

DETAILED DESCRIPTION

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of exemplary embodiments. It should be apparent, however,that exemplary embodiments may be practiced without these specificdetails or with an equivalent arrangement. In other instances,well-known structures and devices are shown in block diagram form inorder to avoid unnecessarily obscuring exemplary embodiments. Inaddition, unless otherwise indicated, all numbers expressing quantities,ratios, and numerical properties of ingredients, reaction conditions,and so forth used in the specification and claims are to be understoodas being modified in all instances by the term “about.”

The present disclosure addresses and solves the current problems ofhaving different (i) substrate, (ii) voltage, (iii) frequency, and (iv)fabrication requirements for digital and analog chips and resultingincreased chip real estate demands and fabrication complexity attendantupon fabricating traditional CMOS devices.

Methodology in accordance with embodiments of the present disclosureincludes forming first trenches in a Si, Ge, III-V, or Si_(x)Ge_(1-x)substrate. A conformal SiN, SiO_(x)C_(y)N_(z), or DPN layer is formedover side and bottom surfaces of the first trenches. The first trenchesare filled with SiO_(x), and a first mask is formed over portions of theSi, Ge, III-V, or Si_(x)Ge_(1-x) substrate. Exposed portions of the Si,Ge, III-V, or Si_(x)Ge_(1-x) substrate are removed, forming secondtrenches. III-V, III-V_(x)M_(y), or Si nanowires are then formed in thesecond trenches. The first mask is removed, and a second mask is formedover the III-V, III-V_(x)M_(y), or Si nanowires and intervening firsttrenches. The SiO_(x) layer is removed, forming third trenches, and thesecond mask is removed.

Still other aspects, features, and technical effects will be readilyapparent to those skilled in this art from the following detaileddescription, wherein preferred embodiments are shown and described,simply by way of illustration of the best mode contemplated. Thedisclosure is capable of other and different embodiments, and itsseveral details are capable of modifications in various obviousrespects. Accordingly, the drawings and description are to be regardedas illustrative in nature, and not as restrictive.

FIGS. 1 through 14 schematically illustrate a process flow for formingSi or Ge-based and III-V-based vertically integrated nanowires on asingle substrate for mixed signal circuits, in accordance with anexemplary embodiment. FIGS. 1, 2, 4 through 12, and 14 arecross-sectional views, and FIGS. 3 and 13 are top views. Adverting toFIG. 1, a SiN layer 101 is deposited, e.g., to a thickness of 2 nm to 30nm, over a Si, Ge, or Si_(x)Ge_(1-x) substrate 103. The upper 50 nm to500 nm of the Si, Ge, or Si_(x)Ge_(1-x) substrate 103 may be doped n+ orp+ prior to forming the SiN layer 101. The Si, Ge, or Si_(x)Ge_(1-x)substrate 103 may be doped, e.g., to form a conducting region for latercontact formation for source-drain definitions. Next, a SiO₂ layer 105is deposited, e.g., to a thickness of 100 nm to 300 nm, over the SiNlayer 101. The SiN and SiO₂ layers 101 and 105, respectively, are thenpatterned, e.g., by reactive ion etching (RIE), as depicted in FIGS. 2and 3.

Adverting to FIG. 4, the Si, Ge, or Si_(x)Ge_(1-x) substrate 103 isetched, e.g., to a depth of 10 nm to 50 nm, forming trenches 401. TheSi, Ge, or Si_(x)Ge_(1-x) substrate 103 may be etched, e.g., with plasmabased species including, but not limited to, bromine trifluoride (BrF₃),chlorine trifluoride (ClF₃), tetrafluoromethane (CF₄), or fluoroform(CHF₃), hydrogen fluoride (HF), boron trichloride (BCl₃), borontrifluoride (BF₃), and sulphur hexafluoride (SF₆). The SiN and SiO₂layers 101 and 105, respectively, are then removed, as depicted in FIG.5. Adverting to FIG. 6, a conformal SiN, SiO_(x)C_(y)N_(z), or DPN layer601 is then deposited on the side and bottom surfaces of the trenches401, e.g., to a thickness of 1 nm to 10 nm, and the remainder of thetrenches 401 is filled with a SiO_(x) layer 603. The SiO_(x) layer 603is then planarized, e.g., by CMP, down to the Si, Ge, or Si_(x)Ge_(1-x)substrate 103, thereby defining the Si, Ge, or Si_(x)Ge_(1-x) nanowires103′. Alternatively, the SiN, SiO_(x)C_(y)N_(z), or DPN layer 601 andSiO_(x) layer 603 may be deposited without first removing the SiN andSiO₂ layers 101 and 105, respectively. Thereafter, all of the layers601, 603, 101, and 105 may be planarized, e.g., by CMP, down to the Si,Ge, or Si_(x)Ge_(1-x) substrate 103, thereby defining the Si, Ge, orSi_(x)Ge_(1-x) nanowires 103′.

A photoresist and hardmask layer 701, e.g., titanium oxide (TiO₂),titanium nitride (TiN), amorphous carbon (a-C), SOH, SOC, SiO₂, or SiN,is formed over the Si, Ge, III-V, or Si_(x)Ge_(1-x) nanowires 103′ withan opening to define III-V growth regions, as depicted in FIG. 7.Portions of the Si, Ge, or Si_(x)Ge_(1-x) nanowires 103′ are then etchedback to form trenches 801, as depicted in FIG. 8. Adverting to FIG. 9,the trenches 801 may be pre-cleaned (not shown for illustrativepurposes), and a metal nanoparticle 901, e.g., Al, Ni, Ga, is depositedin each trench 801 by self-assembly in sol-gel or by direct deposit.Pre-cleaning the trenches 801 helps the nanoparticle 901 to stick to theSi, Ge, or Si_(x)Ge_(1-x) substrate 103 in the trenches 801. The type ofmetal nanoparticles 901 deposited in the trenches 801 also depends onthe type of doping of the Si, Ge, or Si_(x)Ge_(1-x) substrate 103, e.g.,Al or Ga may be deposited for p+ doping and antimony (Sb) or Ti may bedeposited for n+ doping. Alternatively, in-situ doping of arsenic (As),phosphorous (P) (for n+), boron (B), nitrogen (N), Ga (for p+) can bedone during the CVD or VLS growth of the nanowires.

Adverting to FIG. 10, the photoresist of the photoresist and hardmasklayer 701 is removed, leaving just the hardmask 701′, and III-V orIII-V_(x)M_(y) nanowires 1001 are grown to a desired height in thetrenches 801, e.g., by a metal catalyst VLS growth or CVD. Ni, Al, Au,Ag, Ti, Er, Pt, Pd, In, Sn, Sb, Zr, V, Hf, W, Co, Ta, La, Ga, Ru, Mo, orFe may be used as the metal catalyst depending on the type of dopingperformed on the Si, Ge, or Si_(x)Ge_(1-x) substrate 103. Alternatively,the self-assembly of the III-V or III-V_(x)M_(y) nanowires 1001 could beachieved through plasma treatment of the exposed surfaces of trenches801, wet chemistry treatment, or thiol molecule chemistry with axial andradial doping possible. The III-V or III-V_(x)M_(y) nanowires 1001 mayalso completely fill the trenches 801 (not shown for illustrativepurposes). The remainder of masking layer 701 and metal nanoparticles901 are then removed. Next, DPN or direct plasma oxidation (DPO) (notshown for illustrative convenience) is performed to passivate thenanowire surfaces and help with gap-fill. Thereafter, a protective layer1101, e.g., formed of oxide/SOH, is deposited between each III-V orIII-V_(x)M_(y) nanowire 1001 and the sidewalls of the correspondingtrench 801. The protective layer 1101 is then planarized, e.g., by CMP,as depicted in FIG. 11.

Next, a photoresist and hardmask layer 1201 is formed over each III-V orIII-V_(x)M_(y) nanowire 1001 to enable the Si, Ge, or Si_(x)Ge_(1-x)nanowire 103′ regions to be opened, as depicted in FIG. 12. Adverting toFIG. 13, the photoresist and hardmask layer 1201 is then removedresulting in integrated Si, Ge, or Si_(x)Ge_(1-x) nanowires 103′ andIII-V or III-V_(x)M_(y) nanowires 1001 on a single substrate.

Alternatively, the substrate 103 may be formed of III-V material, inwhich case the planarization of the SiO_(x) layer 603 and/or all of thelayers 601, 603, 101, and 105 in FIG. 6 would define the III-V nanowires103′. Further, the opening shown in FIG. 7 would define Si growthregions, and when the photoresist of the photoresist and hardmask layer701 is removed in FIG. 10, leaving just the hardmask 701′, Si nanowires1001 would be grown to a desired height in the trenches 801, e.g., bydepositing a Ni or Au nanoparticle in each trench 801 by self-assemblyin sol-gel, MOCVD, or ALD. Then, the removal of the photoresist andhardmask 1201 in FIG. 13 would result in integrated III-V nanowires 103′and Si nanowires 1001 on a single substrate.

Adverting to FIG. 14, the SiO_(x) layer 603 is removed forming trenches1401, which can be subsequently used to perform source/drain and gateformation steps. The SiN, SiO_(x)C_(y)N_(z), or DPN layer 601 may alsobe removed (not shown for illustrative convenience). Further, shallowtrench isolation regions (not shown for illustrative convenience) mayalso be formed between the Si, Ge, or Si_(x)Ge_(1-x) nanowires 103′ andthe III-V or III-V_(x)M_(y) nanowires 1001 or between the III-Vnanowires 103′ and the Si nanowires 1001 depending on the substratematerial.

FIGS. 15 through 22 (cross-sectional views) schematically illustrateanother process flow for forming Si or Ge-based and III-V basedvertically integrated nanowires on a single substrate for mixed signalcircuits, in accordance with an exemplary embodiment. Adverting to FIG.15, a substrate stack 1501 is sequentially formed with a Si substrate1503, a buffered silicon oxide layer 1505, an a-Si or doped poly-Silayer 1507, a SiN layer 1509, a SiOC layer 1511, and a SiN layer 1513.The particular material composition of the substrate stack 1501 may bedetermined to achieve optimum RIE and wet etch selectivities, e.g., forfabricating gate contacts at a later time. Further, the single substratemay alternatively be formed of Si, SiGe, or a combination thereof.

Adverting to FIG. 16, trenches 1601 and 1603 are formed in the substratestack 1501 down to the a-Si/poly-Si layer 1507 to define the areas forsubsequent nanowire growth. A mask 1701 is then formed over the trenches1603, as depicted in FIG. 17. Next, metal nanoparticles 1703, e.g., Nior Au, are deposited, e.g., by self-assembly in sol-gel or MOCVD, in thetrenches 1601. As described in FIG. 9, the trenches 1603 may bepre-cleaned (not shown for illustrative convenience) to help thenanoparticles 1703 to stick to the a-Si layer 1507. Si, Ge, or Si_(x)nanowires 1801 are then grown by a VLS or CVD process with in-situdoping to the desired height and the mask 1701 is removed, as depictedin FIG. 18.

Next, a mask 1901 is formed over the Si, Ge, or Si_(x) nanowires 1801,and metal nanoparticles 1903, e.g., Al, Ni, or Ga, are deposited, e.g.,by self-assembly in sol-gel or by MOCVD, in the trenches 1603, asdepicted in FIG. 19. Again, the trenches 1603 may be pre-cleaned beforethe metal nanoparticles 1903 are deposited. Thereafter, III-V orIII-V_(x)M_(y) nanowires 2001, e.g., formed of InP or GaAs, are grown toa desired height by a metal catalyst VLS or CVD growth with in-situdoping. Again, Ni, Al, Au, Ag, Ti, Er, Pt, Pd, In, Sn, Sb, Zr, V, Hf, W,Co, Ta, La, Ga, or Fe may be used as the metal catalyst. Alternatively,the self-assembly of the III-V or III-V_(x)M_(y) nanowires 1903 could beachieved through plasma treatment of the exposed surfaces of trenches1603, wet chemistry treatment, or thiol molecule chemistry with axialand radial doping possible. The mask 1901 is then removed, as depictedin FIG. 21. Adverting to FIG. 22, the nanoparticles 1703 and 1903 areremoved, and the Si, Ge, or Si_(x) nanowires 1801 and III-V orIII-V_(x)M_(y) nanowires 2001 are planarized, e.g., by CMP, down to theSiOC layer 1511, forming Si, Ge, or Si_(x)Ge_(1-x) nanowires 1801′ andIII-V or III-V_(x)M_(y) nanowires 2001′. Thereafter, source/drain andgate formation steps may be performed.

The embodiments of the present disclosure can achieve several technicaleffects including heterogeneous integration of Si or Ge-based andIII-V-based channels for vertical FETs on a single substrate enabling,both digital and analog logic to be integrated on a single chip.Integration of self-assembled VLS or CVD growth of nanowires using ametal catalyst with different precursors can also enable the formationof self-aligned vertical nanowires that enable low voltage/power withmultiple scaling options and substantial transistor packing densityrelative to known fin field effect transistor (FinFET) structures.Embodiments of the present disclosure enjoy utility in variousindustrial applications as, for example, microprocessors, smart phones,mobile phones, cellular handsets, set-top boxes, DVD recorders andplayers, automotive navigation, printers and peripherals, networking andtelecom equipment, gaming systems, and digital cameras. The presentdisclosure therefore enjoys industrial applicability with respect to FETstructures with vertical nanowire channels.

In the preceding description, the present disclosure is described withreference to specifically exemplary embodiments thereof. It will,however, be evident that various modifications and changes may be madethereto without departing from the broader spirit and scope of thepresent disclosure, as set forth in the claims. The specification anddrawings are, accordingly, to be regarded as illustrative and not asrestrictive. It is understood that the present disclosure is capable ofusing various other combinations and embodiments and is capable of anychanges or modifications within the scope of the inventive concept asexpressed herein.

What is claimed is:
 1. A method comprising: forming first trenches in asilicon (Si), germanium (Ge), material group III-V, or silicon germanium(Si_(x)Ge_(1-x)) substrate; forming a silicon nitride (SiN) layer overside and bottom surfaces of the first trenches; filling the firsttrenches with silicon oxide (SiO_(x)); forming a first mask overportions of the Si, Ge, III-V, or Si_(x)Ge_(1-x) substrate; removingexposed portions of the Si, Ge, III-V, or Si_(x)Ge_(1-x) substrate,forming second trenches; forming III-V or Si nanowires in the secondtrenches; removing the first mask and forming a second mask over theIII-V or, Si nanowires and intervening first trenches; removing theSiO_(x) layer, forming third trenches; and removing the second mask. 2.The method according to claim 1, further comprising doping an upper 50nanometer to 500 nm of the Si, Ge, III-V, or Si_(x)Ge_(1-x) substrateprior to forming the first trenches.
 3. The method according to claim 1,comprising forming the first trenches by: forming a preliminary SiNlayer over the Si, Ge, III-V, or Si_(x)Ge_(1-x) substrate; forming asilicon dioxide (SiO₂) layer over the preliminary SiN layer; patterningthe SiO₂ and preliminary SiN layers; and etching a portion of the Si,Ge, III-V, or Si_(x)Ge_(1-x) substrate through the patterned preliminarySiN and SiO₂ layers.
 4. The method according to claim 3, furthercomprising removing the SiO₂ and preliminary SiN layers prior to formingthe SiN and SiO_(x) layers in the trenches.
 5. The method according toclaim 1, wherein the substrate is formed of Si, Ge, or Si_(x)Ge_(1-x),the method comprising forming the III-V nanowires by: depositing analuminum (Al), nickel (Ni), or gallium (Ga) nanoparticle in each secondtrench by self-assembly in sol-gel or by direct deposit; and growing theIII-V nanowires to a desired height by a metal catalyst vertical vaporliquid solid (VLS) growth or chemical vapor deposition (CVD).
 6. Themethod according to claim 5, wherein the metal catalyst comprises Ni,Al, gold (Au), silver (Ag), titanium (Ti), erbium (Er), platinum (Pt),palladium (Pd), indium (In), Tin (Sn), antimony (Sb), Zirconium (Zr),vanadium (V), hafnium (Hf), tungsten (W), cobalt (Co), tantalum (Ta),lanthanum (La), Ga, ruthenium (Ru), molybdenum (Mo), or iron (Fe). 7.The method according to claim 6, wherein the III-V nanowires are notgrown to a full width of the second trenches, the method furthercomprising: forming an oxide or nitride layer between each III-Vnanowire and sidewalls of the corresponding second trench.
 8. The methodaccording to claim 1, wherein the substrate is formed of III-V, themethod comprising forming the Si nanowires by: depositing a nickel (Ni)or gold (Au) nanoparticle in each second trench by self-assembly insol-gel, metal organic chemical vapor deposition (MOCVD), or atomiclayer growth (ALD); and growing the Si nanowires to a desired height.